Wireless communication systems may operate using fixed infrastructure equipment or in ad-hoc configurations. In fixed infrastructure models, wireless communication systems typically comprise a plurality of base stations and mobile stations that communicate using an over-the-air communication protocol using physical layer technologies such as Code Division Multiple Access (CDMA) technology. IS-95, Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System, published in July 1993 is an example of such a protocol standard. CDMA uses digital spread spectrum techniques that are less susceptible to interference.
Wireless communications systems such as CDMA typically operate using a variety of channels. In CDMA, for example, channelization is accomplished using orthogonal or quasi-orthogonal codes. Different channels generally have different purposes. Common channels are used to communicate to a plurality of mobile stations or base stations at the same time while dedicated channels are typically used for communication to and from one mobile station.
Wireless communication systems are beginning to incorporate network-based and network-assisted location determination systems. Some wireless handsets have network assisted GPS capability. Some CDMA wireless handsets make use of the wireless communication signals themselves to perform location-related measurements such as in Enhanced Forward Link Trilateration (EFLT) or Advanced Forward Link Trilateration (AFLT) methods that use the difference in phase delays of wireless signals as input to location calculations. Other wireless communication systems, such as some telematics products incorporate stand-alone capabilities such as GPS. Wireless terminals without location capabilities may also have access to location related information. For example, the base station that a mobile station communicates with may have a unique identifier that identifies that particular base station to the mobile or signal conditions may be recognized from past observations. These types of information inherently identify the mobile station's general location as being the same as at some prior time.
Location information can be used to enable location-based services. Similarly, location-based services can be network or terminal based or distributed between wireless communication system entities. Distributed or network based services generally require active communication and use of wireless resources such as communication channels. For example, the TIA/EIA location protocol standard IS-801 enables network-assisted GPS via messaging over the CDMA wireless link between infrastructure and terminals. Such resources may be expensive, limited and have quality of service impacts on usage such as moderate or high latency.
Networks typically transmit location-related information or identification information to mobile stations. However, such information is typically limited to idle state while channels used for connections do not typically transport as much location or identification related information. For example, IS-95A systems typically broadcast base station identification and base station latitude and longitude information on common channels that mobile stations monitor in idle state. These systems typically do not transmit such information on dedicated traffic channels. Additionally, mobile stations typically monitor only one sector at a time during idle. This limits the amount of information that a mobile station can observe. Therefore, according to existing standards and implementations, mobile stations do not have adequate access to location-related information.
What is needed is a method of obtaining and using location-related information associated with wireless communication infrastructure.